Wireless communications systems typically include a plurality of base stations, each servicing mobile nodes within an associated coverage area. As a mobile node roams between base stations, it is desirable to transition active mobile sessions to the new base station. For example, it is desirable to have real-time or streaming applications such as Voice-over-Internet Protocol (VoIP) continue without interruption and without loss of data packets. The user experience can be adversely affected if there are lengthy processing delays or other interruptions during the handoff process.
In a conventional handoff process, a mobile node first detects the new base station and negotiates a new communications link, which may include a new mobile IP address (“care of address”) when the mobile node changes subnetworks. The mobile node next notifies its home network of the current binding between its home address and the mobile IP address. The home agent ensures that the mobile node maintains connectivity with the Internet as it traverses subnetworks.
During the handoff process, the destination base station polls the wireless communications system to determine the user's context so that mobile node's current Class of Service (CoS) can be maintained after the handoff. Context information may include data relating to security, policy, Quality of Service (QoS), header compression and other information. Retrieving and establishing the mobile node's current context at the destination base station router is time consuming and may delay the handoff. Further delays may be found where the source and destination base stations operate on different subnets, or with different technologies or protocols.
In view of the above, there is a need for an improved system and method for handling handoff processing.